MO237: Rituximab in Treatment of Minimal Change Disease and Primary Focal Segmental Glomerulosclerosis in Adults-Single Center Experience

BACKGROUND AND AIMS

Rituximab (RTX) showed some efficacy in treatment of minimal change disease (MCD) and primary focal segmental glomerulosclerosis (pFSGS) [1]. The results of its off-label use and as steroid-sparing agent were especially promising in steroid-dependent, frequently relapsing or steroid-resistant forms of MCD and pFSGS in adults [2].

METHOD

All patients treated with RTX in Department of Nephrology and Dialysis, University Hospital Dubrava, Zagreb, were retrospectively reviewed. Complete remission (CR), steroid-resistant nephrotic syndrome (SRNS), steroid-dependent nephrotic syndrome (SDNS), multidrug-resistant SRNS (MDR-SRNS) and calcineurin inhibitor (CNI)-resistant SRNS were defined according to KDIGO 2021 [3].

RESULTS

Of 82 patients treated with RTX, 11 patients had biopsy proven MCD and pFSGS. Table 1 summarizes relevant demographic, clinical and treatment data. RTX was applied in five patients with SDNS, four patients with MDR-SRNS, one patient with CNI-resistant SRNS and one patient with active hepatitis C and newly onset MCD as a first line therapy. Median follow-up after initial diagnosis and RTX application was 122.9 (range 30–219) and 20 (range 3–117) months, respectively. All patients were initially treated with steroids, and RTX was the drug most commonly applied after treatment with CNI and cyclophosphamide (CYC). Median proteinuria at the time of RTX application was 10 g/day (range 2.5–16.7), 10 patients had preserved kidney function and only 1 patient with collapsing FSGS (case 11) had severe acute kidney injury. Mean cumulative dose of RTX for induction was 1700 mg and short course of steroids was used concomitantly in 10 cases (except case 5). CR was achieved in seven cases (six cases of MCD and one case of MDR-FSGS). Three of seven patients with CR to RTX experienced relapse of disease. Time to relapse was 6, 15 and 40 months in case 5, 3 and 11, respectively. Repeated RTX application led to CR in all three cases. CR persisted in five patients even after the steroids cessation. There were no serious adverse effects of RTX administration in our cohort.

CONCLUSION

RTX showed respectable efficacy in our cohort of adults with SDNS-MCD and in case of MDR collapsing FSGS. Although statistical comparison was not performed because of small number of patients, it seems that RTX is more effective in group of SDNS than MDR-SRNS. In our cohort, patients with relapse of RTX-sensitive disease responded to repeated application. Role of RTX in treatment of MCD and pFSGS should be evaluated in randomized clinical trials.

The switch from proteasome to immunoproteasome is increased in circulating cells of patients with fast progressive immunoglobulin A nephropathy and associated with defective CD46 expression

The proteasome to immunoproteasome (iPS) switch consists of β1, β2 and β5 subunit replacement by low molecular weight protein 2 (LMP2), LMP7 and multicatalytic endopeptidase-like complex-1 (MECL1) subunits, resulting in a more efficient peptide preparation for major histocompatibility complex 1 (MHC-I) presentation. It is activated by toll-like receptor (TLR) agonists and interferons and may also be influenced by genetic variation. In a previous study we found an iPS upregulation in peripheral cells of patients with immunoglobulin A nephropathy (IgAN). We aimed to investigate in 157 IgAN patients enrolled through the multinational Validation Study of the Oxford Classification of IgAN (VALIGA) study the relationships between iPS switch and estimated glomerular filtration rate (eGFR) modifications from renal biopsy to sampling. Patients had a previous long follow-up (6.4 years in median) that allowed an accurate calculation of their slope of renal function decline. We also evaluated the effects of the PSMB8/PSMB9 locus (rs9357155) associated with IgAN in genome-wide association studies and the expression of messenger RNAs (mRNAs) encoding for TLRs and CD46, a C3 convertase inhibitor, acting also on T-regulatory cell promotion, found to have reduced expression in progressive IgAN. We detected an upregulation of LMP7/β5 and LMP2/β1 switches. We observed no genetic effect of rs9357155. TLR4 and TLR2 mRNAs were found to be significantly associated with iPS switches, particularly TLR4 and LMP7/β5 (P < 0.0001). The LMP7/β5 switch was significantly associated with the rate of eGFR loss (P = 0.026), but not with eGFR at biopsy. Fast progressors (defined as the loss of eGFR >75th centile, i.e. -1.91 mL/min/1.73 m2/year) were characterized by significantly elevated LMP7/β5 mRNA (P = 0.04) and low CD46 mRNA expression (P < 0.01). A multivariate logistic regression model, categorizing patients by different levels of kidney disease progression, showed a high prediction value for the combination of high LMP7/β5 and low CD46 expression.

P0456LONG TERM PATIENT SURVIVAL AND RELAPSE RATE IN ANCA ASSOCIATED PATIENTS WITH RENAL INVOLVMENET - DATA FROM CROATIAN REFERRAL CENTER

Background and Aims

The aim of the research was to evaluate patient and renal as well as relapse free survival in ANCA associated vasculitis (AAV) patients in our center. Despite the advances in understanding pathogenesis of AAVs and advances in treatment, the outcomes of AAV patient differ in various centers.

Method

This study included 106 consecutive AAV patients with renal involvement in the period from 2007-2017. We performed renal biopsy on patients using automatic 16 Gauge needle. Light, immunofluorescent and electronic microscopy were performed. All the patients were treated with cyclophosphamide and steroids in induction treatment with adjuvant PLEX and dialysis depending on renal function and lung manifestations.

Primary outcomes were combined outcome progression to end-stage renal disease, defined as persistent (more than three months) need for renal replacement therapy or permanent reduction of EGFR to &lt;15ml/minute (according to CKD EPI formula) and/or death (ESRDD), death (D) and ESRD alone, and disease relapse. Kaplan Meyer survival analysis and multivariate Cox proportional hazard regression analysis were used to explore difference between phenotypes and finding significant predictors regarding outcomes.

Out of 106 patients (55,6% female, median age 61; IQR 51-70) there were 66 (61,1%) microscopic poliangitiis (MPA), 20 (18,5%) granulomatosis with angitiis and 20 (18,5%) with renal limited vasculitis (RLV),There were 14 (13%) PR3-ANCA positive patients, 57 (52,8%) MPO ANCA positive, 5 (4,6%) PR3-ANCA+MPO-ANCA positive and 32 (29,6%) ANCA negative patients. Histologically (Berden classification) 43 (39,8%) patients had crescentic, 19 (17,6%) focal, 34 (31,5%) mixed and 12 (11,1%) sclerotic class. Follow up time ranged from 1 to 127 months. Median follow up time was 21 months (IQR = 7-44). Median time to diagnosis was 3 months (IQR 2,0-6,0).

Results

During follow up 21 (19,8%) patients died, 26 (24,5%) patients reached ESRD and 10 (9,4%) patients relapsed. There was no significant difference in outcomes between clinical, serological or histological phenotypes. In multivariant analysis independent predictors for death were age (HR = 1,059, 95% CI =1,001-1,120; p = 0,046), anemia (HR = 0,952, 95% CI =0,908-0,998; p = 0,040) and BVAS (HR = 1,093, 95% CI =1,030-1,159; p = 0,003), for ESRD. the need for acute dialysis (HR = 4,674, 95% CI =1,996-10,946; p = &lt; 0,001), and interstitial fibrosis and tubular atrophy (IFTA) percentage over 50% (HR = 2,652, 95% CI =1,157-6,081; p = 0,021). and for relapse rate younger age (HR = 0,924, 95% CI = 0,870-0,981; p =0,010), lower serum creatinine levels (HR = 0,996, 95% CI = 0,992-1,000; p = 0,033), and the need for acute dialysis (HR = 59,545, 95% CI =3,467-1022,665; p = 0,005). Event free survival after 12, 24, 36 and 60 months was for death 83,9, 81,2, 79 and 74,7%, for ESRD 80,6, 77,9, 76,1 and 71% and for relapse 95,3, 88,4, 88,4 and 85%.

Conclusion

Timely diagnosis and treatment can ensure better outcomes in AAV patients. Though there is an overlap in predictive factors between different cohorts, there are still distinctive differences especially between cohorts from clinical trials and those from observational studies. Our study is among few to show significance of anemia as clinical predictor and IFTA percentage as pathohistological predictor.

P0471DIALYSIS TREATMENT AT THE TIME OF DIAGNOSIS PREDICTS OUTCOMES IN ANCA ASSOCIATED VASCULITIS PATIENTS - DATA FROM CROATIAN REFERRAL CENTER

Background and Aims

Dialysis dependence and ESRD are known complications of ANCA associated vasculitis (AAV) with renal involvement. What is not so often discussed is the role of dialysis treatment at the time of diagnosis and how it affects patient outcomes as well as characteristics of such patients. We present data showing the importance of dialysis treatment at the time of diagnosis as the predictor of clinical outcomes.

Method

This study included 106 consecutive AAV patients with renal involvement in the period from 2007-2017. We performed renal biopsy on patients using automatic 16 Gauge needle. Light, immunofluorescent and electronic microscopy were performed.

Primary outcomes were combined outcome progression to end-stage renal disease, defined as persistent (more than three months) need for renal replacement therapy or permanent reduction of EGFR to &lt;15ml/minute (according to CKD EPI formula) and/or death (ESRDD), death (D) and ESRD alone, and disease relapse. Kaplan Meyer survival analysis and multivariate Cox proportional hazard regression analysis were used to explore difference between phenotypes and finding significant predictors regarding outcomes.

Results

Out of 106 patients (55,6% female, median age 61; IQR 51-70) there were 66 (61,1%) microscopic poliangitiis (MPA), 20 (18,5%) granulomatosis with angitiis and 20 (18,5%) with renal limited vasculitis (RLV). Out of those 14 (13%) were PR3-ANCA positive patients, 57 (52,8%) MPO ANCA positive, 5 (4,6%) PR3-ANCA+MPO-ANCA positive and 32 (29,6%) ANCA negative patients. Average serum creatinine (SCr) levels was 316,5 μmol/l (IQR 207,0-548,5), 24-hour proteinuria median was 1,7g/24h (IQR 0,8-2,8). According to the Berden classification 43 (39,8%) patients had crescentic, 19 (17,6%) focal, 34 (31,5%) mixed and 12 (11,1%) sclerotic class. Follow up time ranged from 1 to 127 months. Median follow up time was 21 months (IQR = 7-44). Median time to diagnosis was 3 months (IQR 2,0-6,0). Patients requiring dialysis treatment at the time of diagnosis were more often MPO – (p=0,04), had more severe anemia (p=0,001), higher CRP (p=0,003), and more pronounced hypoalbuminemia (serums albumin &lt;30g/l; p=0,006).Such patients were older than those not requiring dialysis (p=0,055) na had shorter time to diagnosis (p=0,001). Clinically such patient s presented more often with RPGN (p&lt;0,001) which is in a way expected thus having higher SCr levels (p=&lt;0,001). Histologically dialysis treated patients predominantly had crescentic class, while non-dialysis group had focal class (p&lt;0,001). Of note dialysis group had more acute tubular damage (p=0,007). Interestingly enough there was slightly more positive C3 deposition in dialysis group (p=0,09). In univariate analysis the need for acute dialysis at the time of diagnosis of AAV was significant predictor for combined ESRDD, D, ESRD and relapse rate. In multivariate analysis the need for acute dialysis at the time of diagnosis of AAV remained significant predictor for ESRD (HR = 4,674, 95% CI =1,996-10,946; p = &lt; 0,001) and relapse rate (HR = 59,545, 95% CI =3,467-1022,665; p = 0,005).

Conclusion

The need for dialysis at the time of AAV diagnosis is a strong predictor for ESRD and relapse rate. It is also interesting to further study differences between patients needing dialysis at the time of diagnosis and those who don’t need it.

P0427IGA GLOMERULONEPHRITIS WITH MASSIVE PROTEINURIA- CASE SERIES WITH CLINICAL AND PATHOHISTOLOGICAL REVIEW

Background and Aims

IgA nephropathy (IgAN) is the most common glomerulonephritis worldwide. The classic manifestation of IgAN is episodic hematuria and proteinuria. Nephrotic syndrome (NS) is not common in IgAN. It is reported to occur in 5-10% of patients with IgAN. Clinical presentation with massive proteinuria is exceptional.

Method

We retrospectively analyzed patients with pathohistologically proven IgAN who initially presented with 24h proteinuria greater than 10 gr. Here we presented their clinical, biochemical and pathohistological (electron microscopy-EM, was provided in all cases) characteristics with clinical outcomes. Data were taken from Renal biopsy Registry of Department of Nephrology Dubrava University hospital.

Results

All together 12 patients (10 M, 2 F) average age 53 (range 25-81) years were included. This represents 3,2% of all IgAN patients in our Renal biopsy Registry (presently there are more than 2100 patients in total, 366 with IgAN). Arterial hypertension had 10 out of 12 patients and three patients had diabetes mellitus type 2. Other significant comorbidities included lung adenocarcinoma in one patient, history of preeclampsia, mitral valve replacement surgery and liver cirrhosis, each in one patient. Average serum creatinine level at presentation was 223,9 (90-549) µmol/L and average 24h proteinuria was 14,6 (10,2-32) gr. All patients had haematuria. Renal insufficiency was found in 7 patients and additionally in two patients rapidoprogressive clinical pattern was recognized. Oxford classification was applied for all patients. In all except one, mesangial hypercellularity (M1) was found, endocapillary proliferation (E1) in 4 and cellular crescents in 5 patients (C1 in 4, C2 in 1 patient). The average percentage of globally sclerosing glomeruli was 32% (10-85%) and IFTA was 33% (10-60%), respectively. On EM diffuse podocyte foot processes effacement was documented only in two patients. In patients with diabetes mellitus there were not signs of diabetic nephropathy (i.e. thickened GBM on EM). Two patients who presented with purpuric rash and arthritis were considered to have IgA vasculitis (Henoch Schoenlein purpura). Considering treatment, glucocorticosteroids and RAAS blockators (apart from those who were dialysis dependent) were introduced. Five patients were also treated with cyclophosphamide. Average time of follow-up was 53 months (2-156). Regarding clinical outcomes, 4 patients achieved remission (2 partial and 2 complete). One of those experienced clinical relaps and underwent kidney rebiosy. In one patient stationary course and in another one progression of renal insufficiency were noted. Both patients diagnosed as IgA vasculitis were dialysis depended at presentation and during follow-up period unfortunately died. Two more patients died latter on as a consequence of a non-renal disorders. One more patient who developed ESRD was transplanted but afterwards he rejected the graft. One patient was lost from follow-up.

Conclusion

Proteinuria is well known independent progression risk factor in IgAN. In presented study we showed that almost one third of IgAN patients who manifested with massive proteinuria ended up in ESRD in relatively short follow-up period.

Defective gene expression of the membrane complement inhibitor CD46 in patients with progressive immunoglobulin A nephropathy

BACKGROUND

Complement is thought to play a role in immunoglobulin A nephropathy (IgAN), though the activating mechanisms are unknown. This study focused on the gene expression of CD46 and CD55, two key molecules for regulating C3 convertase activity of lectin and alternative complement pathways at a cellular level.

METHODS

The transcriptional expression in peripheral white blood cells (WBCs) of CD46 and CD55 was investigated in 157 patients enrolled by the Validation of the Oxford Classification of IgAN group, looking for correlations with clinical and pathology features and estimated glomerular filtration rate (eGFR) modifications from renal biopsy to sampling. Patients had a previous median follow-up of 6.4 (interquartile range 2.8-10.7) years and were divided into progressors and non-progressors according to the median value of their velocity of loss of renal function per year (-0.41 mL/min/1.73 m2/year).

RESULTS

CD46 and CD55 messenger RNA (mRNA) expression in WBCs was not correlated with eGFR values or proteinuria at sampling. CD46 mRNA was significantly correlated with eGFR decline rate as a continuous outcome variable (P = 0.014). A significant difference was found in CD46 gene expression between progressors and non-progressors (P = 0.013). CD46 and CD55 mRNA levels were significantly correlated (P < 0.01), although no difference between progressors and non-progressors was found for CD55 mRNA values. The prediction of progression was increased when CD46 and CD55 mRNA expressions were added to clinical data at renal biopsy (eGFR, proteinuria and mean arterial blood pressure) and Oxford MEST-C (mesangial hypercellularity, endocapillary hypercellularity, segmental glomerulosclerosis, tubular atrophy/interstitial fibrosis, presence of any crescents) score.

CONCLUSIONS

Patients with progressive IgAN showed lower expression of mRNA encoding for the complement inhibitory protein CD46, which may implicate a defective regulation of C3 convertase with uncontrolled complement activation.

Is there long-term value of pathology scoring in immunoglobulin A nephropathy? A validation study of the Oxford Classification for IgA Nephropathy (VALIGA) update

Background

It is unknown whether renal pathology lesions in immunoglobulin A nephropathy (IgAN) correlate with renal outcomes over decades of follow-up.

Methods

In 1130 patients of the original Validation Study of the Oxford Classification for IgA Nephropathy (VALIGA) cohort, we studied the relationship between the MEST score (mesangial hypercellularity, M; endocapillary hypercellularity, E; segmental glomerulosclerosis, S; tubular atrophy/interstitial fibrosis, T), crescents (C) and other histological lesions with both a combined renal endpoint [50% estimated glomerular filtration rate (eGFR) loss or kidney failure] and the rate of eGFR decline over a follow-up period extending to 35 years [median 7 years (interquartile range 4.1–10.8)].

Results

In this extended analysis, M1, S1 and T1–T2 lesions as well as the whole MEST score were independently related with the combined endpoint (P &lt; 0.01), and there was no effect modification by age for these associations, suggesting that they may be valid in children and in adults as well. Only T lesions were associated with the rate of eGFR loss in the whole cohort, whereas C showed this association only in patients not treated with immunosuppression. In separate prognostic analyses, the whole set of pathology lesions provided a gain in discrimination power over the clinical variables alone, which was similar at 5 years (+2.0%) and for the whole follow-up (+1.8%). A similar benefit was observed for risk reclassification analyses (+2.7% and +2.4%).

Conclusion

Long-term follow-up analyses of the VALIGA cohort showed that the independent relationship between kidney biopsy findings and the risk of progression towards kidney failure in IgAN remains unchanged across all age groups and decades after the renal biopsy.

Clinical, serological and histological determinants of patient and renal outcome in ANCA-associated vasculitis with renal involvement: an analysis from a referral centre

PURPOSE

To evaluate significance of clinical and histopathological prognostic factors for renal and patient outcome in AAV patient cohort.

METHODS

Retrospective study included consecutive patients diagnosed with pauci-immune crescentic glomerulonephritis from January 2003 to December 2013. Primary outcome was combined endpoint patient death or progression to end-stage renal disease (ESRD). Secondary outcomes were patient survival and progression to ESRD (renal survival) singularly and disease relapse. Kaplan-Meyer survival analysis and multivariate Cox proportional hazard regression analysis were used to explore difference between phenotypes and finding significant predictors regarding outcomes.

RESULTS

Out of 81 patients, 40.7% patients reached primary endpoint, 22.2% died, 29.6% reached ESRD and 16% relapsed during follow-up. Multivariate Cox proportional hazards regression-adjusted analysis found higher BVAS (HR 1.08, 95% CI 1.01-1.17, p = 0.042), higher baseline maximal serum creatinine (HR 1.02, 95% CI 1.01-1.03, p = 0.04) and lower haemoglobin (HR 0.97, 95% CI 0.95-0.99, p = 0.011) significantly associated with primary endpoint. Higher BVAS (HR 1.25, 95% CI 1.01-1.43, p = 0.001) and lower haemoglobin (HR 0.95, 95% CI 0.91-0.99, p = 0.008) were significantly associated with patient survival, while for renal survival, lower haemoglobin (HR 0.97, 95% CI 0.94-0.99, p = 0.041) and the need for acute haemodialysis (HR 3.15, 95% CI 1.20-8.26, p = 0.02) were significant predictors. On multivariate-adjusted analysis, no significant predictors for disease relapse were found. Kaplan-Meier survival analysis found no difference between clinical, serological and pathohistological phenotypes for all of the endpoints.

CONCLUSIONS

Renal function at presentation, anaemia and BVAS should be included in prediction models for the outcomes for the AAV patients.